Prosthetic appliances



w.v c. oLlvER PROSTHETI C APPLIANCES June 11, 1957 2 She'ets-Sheet 1 Filed April 16, 1953 IN VEN TOR. Wilbur C. Oliver gli d Y M72 Attorneys June 1l, 1957 w. c. oLlvER 2,794,987

PROSTHETIC APPLIANCES Filed April 16. 1953 2 Sheets-Sheet 2 Attorneys Unite' The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to prosthetic appliances yand particularly to an artificial leg for above-the-knee amputees.

While many designs of artificial legs have been made,

none to the present time have, when applied to the amputee, provided completely satisfactory results. Particularly, the lack of simulation of the action of a natural .leg has been apparent, and results in a certain embarrassment for the amputee as well as actual difficulty in Walking.

An object of the present invention is to provide an artificial leg for above-the-knee amputees which incorporates an improved knee mechanism enabling ambulatory motion closely approximating inappearance that of a 4natural leg.

OtherV objects and many of the attendant advantages yof this invention will be readily appreciated as the same becomes better understood by reference to the following "detailed description `when considered in connection with the accompanying drawings wherein:

Fig. l is an isometric view of the knee portion of an artificial leg, parts being broken away to illustrate interior construction;

Fig. 2 isa transverse sectional view of the kneetaken along line 2--2 in Fig. 3;

' Fig. 3 is a sectional view taken along line 3-3 of Fig. 2 to show certain details of construction; and

Fig. 4 is an isometric view of part of the knee structure when sectionally broken along line 4-4 in Fig. 2.

The artificial leg of the present invention includes a shin portion pivotally suspended from a thigh portion 11 and having a foot (not shown) suitably secured to itslower end. The thigh portion 11 is adapted for iitted attachment to the stump of an amputee in a known manner and, as shown in the drawings,is preferably of 'hollow basswood construction as indicated at 11a` so as to be relatively light but of sufficient rigidity and strength 'to bear the weight of the amputee. The shin-portion 10 -is also of hollow construction, being fashioned of a reinforced plastic as shown at 10a, although other material `can be employed either for the shin or thigh portions of a leg, if desired. Both the shin portion 10 and the thigh ,portion 11 are covered with raw-hide as indicated at 10b -and 11b, respectively, and are generally fashioned in the manner well known in this art s o as to provide ythe optimum cosmetic qualities.

1 :To provide the mentioned pivotal suspension' of the A.shin portion 10 of the leg from the thigh portion 11 ,-thereof, a pair of rigid rnetal straps 12, 13 are secured by rivets 14 ,to the interior off the shin portion and on "opposite sides thereof so as to extend upwardly a slight .distance above the upper extremity of the vshin portion 1t) for attachment to the ends of a tubular shaft 15 extendingthrough -a transverse bore 16 (Fig. 2) rformed States Patent Patented June 1l, 1957 in the thigh portion 11 of the leg. To provide the attachment each strap 12, 13 is provided with a tapered hole 17 arranged to encompass the tapered exterior of the tubular shaft 15 and is held thereon by a bolt 18 `which is screwed into the threaded interior of the shaft.

The straps 12, 13 are held by felt spacers 20 in outwardly spaced relation from a pair of bearings generally indicated at 19, heldl in the thigh portion 11 of the leg so as to rotatably support the shaft 15. Three distinct means for controlling rotation of the shaft include several elements which engage its exterior at positions between the two bearings 19, as will be described in detail hereinafter.

The mentioned bearings 19 are preferably self-aligning and to this end each bearing comprises a pair of sleeves 2l, 22, one held in resilient movable contact within the other. Since the two bearings are identical in construction only one need by described, like numerals on the drawings indicating like parts thereof. As shown clearly in Fig. 2, the outer sleeve 21 is pressed or otherwise secured within the described bore 16 in the thigh portion 11 of the'leg and has an inturned shoulder 21a formed at its inner end adapted to abut an outturned shoulder 22a on the inner sleeve 22 when the latter is telescoped thereinto. A rubber collar 23 is inserted between the two sleeves 21, 22 and is compressed therebetween, much in the manner of a packing, by the insertion of an exteriorly threaded ring or gland 24 into the internally threaded end of the outer sleeve 21'. Radial clearances, as shown at 25, 26, and 27 in Fig. 2, enable the inner sleeve 22, whose interior provides the bearing surface for the described shaft 15 to be moved into axial misalignrnent relative to the outer sleeve 21 against the resiliency of the rubber collar 23. As a consequence, the two sleeves 22 will automatically align themselves with one another on the shaft 15 regardless of warping of the wooden thigh so that harmful binding effects on the pivotal movement of the shin portion 10 of the leg will be precluded. Preferably, the inner sleeve 22 is of a self-lubricating bronze and is longitudinally slotted as shown at 22b in Fig. 1 so that the gland 24 can be tightened to compress the rubber collar 23 and consequently exert radial pressure inwardly against the slotted sleeve to establish a firm rotatable support for the shaft 15.

Adjacent the inner end of one bearing 19, one of the mentioned control means, which preferably comprises an adjustable brake, is arranged to constantly retard rotation of the shaft 15 within the bearings 19. As shown, this brake can conveniently be in the form of a U-shaped clamp 30 surrounding the shaft 15 and pressing an oilimpregnated leather brake-lining 31 against the shaft with a pressure determined by a clamp-screw 32 which adjustably connectsV the free ends or legs 30a, 30b of the U-shaped clamp 30. One leg 30a of the, clamp 30 is secured to the thigh portion 11 of the leg, as shown at 33 in Fig. 1, but any equivalent means for securing the clamp can be employed. Ascan best be visualized with reference to Fig. 3, when the clamp screw 32 is rotated to pull the legs 30a, 301) of the U clamp 3) toward one another, increased pressure of the brake-lining 31 against the shaft 15 will result and consequently provide greater frictional resistance to pivoting of the shin portion 10 with respect to the thigh portion 11 throughout the cornplete walking cycle of the artificial leg.

As shown in Fig. 4, additional resistance to turning or pivoting of the shin portion 10 ofthe leg is provided by another control means comprising a second brake, which, however, in accordance with the present invention, is operable only during certain portions of the walking cycle. Like the first mentioned-brake, the second brake is in the form of a U clamp 35 which adjustably presses 3v an oil-impregnated leather brake-lining 36 against the shaft 15,the braking pressure being adjusted by a clampscrew 37 which connects the legs 35a, 35h of the clamp. -From vone 'leg 35h` of the U clamp, iintegraltears 38, 39 extend.outwardly at substantially right angles `relative to one another and `respectively support rubber bumpers 40, 41 thereon. These bumpers 4t), 4l are adapted, when the shaft 15 rotates within its supporting bearings 19,"to engage stops 42, "43 which. canbe an integral part of the' thigh portion 11 ofthe leg, or alternatively, sepa rate `small blocks secured thereto. Consequently, the shin portion 1t) of the leg rotates relative to the thigh portion 11, thereof and the shaft 15 thus rotates in the bearings 119, the U clamp 35, due to its frictional connection with the shaft 15 rotates withthe latter until one of the bumpers 4t) or 41 engages its respective stop 42 or `43 whereupon further rotation of the clamp is precluded and resistance, in addition to that provided by the first-described brake, results to increase the decelerating force or torque applied to the shin portion of the leg during its pivotal movement. The described stops 42,43 are positioned so that after a predetermined amount of travel of the shin portion 10 of the leg from a position of extension or flexion, one or the other of the stops is engaged by the respective bumper 4G or 41 on the second brake. Accordingly, it can be seen that depending upon the adjustment of the two brakes the shin portion of the leg will proceed from an extended or flexed position at a rate controlled fora predetermined period only by the first brake, but for the remainder of its pivotal movement under the control of both brakes. The adjustments are of course made in accordance with the individual require ments of the amputee so that the walking cycle of the artificial leg will correspond for each step with that of the natural leg both in the rate and in the number of degrees or amount of pivotal movement of the shin.

Between the described brakes, an arm 45 is secured at itsupper end to the shaft so as to determine the limit of `the pivotal movement of the shin portion 1t) of the leg in each direction. Inaccordance with the present invention and as best shown in Fig. l, the upper end of the arm is provided with a transverse, circular opening 46 witha slot 47 extending radially outward therefrom. A sleeve 48, preferably of self-lubricating bronze and being slotted .as shown at 48a, is positioned within the opening 46 and is pressed againsty the exterior of the shaft 1S to a degree determined by the tightening or loosening of a clamp-screw 49. The arm 45 is secured on the shaft 15 so that its lower extremity abuts the posterior of the shin portion 10 of the leg, a `rubber bumper 50 being secured at this extremity to cushion the engagement. Since the shin 10 rotates with the shaft 15 and the arm 45 `is secured in frictional engagement therewith, the arm normally remains in the described position with its lower extremity abutting the posterior of the shin portion 10 of the leg. As the shin portion 10 is extended, another rubber bumper 51 mounted on the foreside of the arm 45 intermediate its extremities approaches a portion of the thigh as indicated at 52 and, as can best be seen in Fig. 3,

engagement of the bumper 51 with this portion of the thigh 11 precludes further pivotal movement of the shin portion 10 of `the leg forwardly, thus determining the limiting position of extension. So that the amputee may rest in a standing position `on the leg when the shin portion is thus fully extended, the described position is such that the weight-bearing line of the leg, indicated at W in Fig. 3, passesupwardly on the forward or left side of thesbaft 15.`

As the shin portion 10 of the leg is flexed rearwardly, the arm 45 moves therewith until an intermediate section thereof on its rear side engages another portion of the basswood thigh as indicated at 53, thus normally limiting the amount of permissible exion. However, since Vthe arm 45 is secured to the shaft 15 for rotation therewith only as a consequence of the pressure of the oilite sleeve 48 thereon, further flexionot the shin portion 10 of the lcg is permitted, with the arm 45, consequently, swinging relatively forwardly from the posterior of the shin portion 19 toward the anterior thereof. In this manner, an ampntee even though his leg stump be quite long (i. e., amputation performed immediately above the knee), is enabled to bend the shin portion 10 of his leg considerably past a right-angle position with respect to the thigh portion i1.

When an artificial leg of the described type has been fitted on an amputee, the arm 45 is clamped to the shaft 15 by tightening of the screw 49 in a rotative position such that the arm is normally maintained in contact with the rear of the shin through the bumper 50. The amputee then walks observing the rate and amount of pivotal movement of the shin portion 10 of the leg. The screws 32 and 37 which control the two brakes, respectively, are then adjusted, repeatedly if necessary, to produce a pivotal movement corresponding in rate and amount to that of the natural leg. It has been found that by careful ad justment of the screws 32 and 37, simulation of the walking cycle of a natural leg can be so closely approximated that an ordinary observer is not able to ascertain which of an amputees legs is the artificial one.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. In particular, various other equivalent control `means can be substituted for the described brake .structures so long as the desired retarding of the pivotal movement of the shin portion of the leg can be obtained therewith. lt is therefore `to be understood that within .the scope `of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises means pivotally mounting the shin portion on the thigh portion of the leg for movement between flexed and extended positions, and control means operative in response to a predetermined amount of pivotal movement ofthe shin portion from one of said positions toward the other to retard further pivotal movement.

2. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism com prises means pivotally mounting the shin portion on the thigh portion of the leg for movement between` flexed and extended positions, and control means operative in response to a predetermined amount of pivotal movement ofthe shin portion from one of said positions toward `the other to provide frictional resistance to further pivotal movement.

3. A knee mechanism according to claim 2 comprising `means for adjusting Vsaid control means to vary the frictional resistance provided thereby.

4. A` knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises means pivotally mounting the shin portion `on the thigh portion of the leg for movement between flexed and extended positions, first control means in operative engagement with said mounting means to retard the pivotal movement, and second control means operative in response to a predetermined amount of pivotal movement of the shin portion from one of said positions toward the other to provide added resistance to further pivotal movement.

5. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises means pivotally mounting `the shin portion on the thigh portion for flexion and extension, means for limiting the vpivotal movement in both directions, and control means operative in response to a predetermined `amount of pivotal movement of the shin portion to retard further pivotal movement.

6. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises a shaft rotatably supported by the thigh portion of the leg, means for securing the shin portion to said shaft for pivotal movement with respect tothe thigh portion between ilexed and extended positions, a brake lining engaging said shaft, a U-shaped clamp encompassing said lining, means adjustably connecting the extremities of said U-shaped clamp for varying the braking pressure of said lining on said shaft, and means including a pair of projections yon said clamp arranged to contact the thigh portion of the leg upon predetermined pivotal movement of the shin portion of the leg from one of said positions toward the other.

7. A knee mechanism according to claim 6 wherein said brake lining is composed of oil-impregnated leather.

8. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises a shaft rotatably supported by the thigh portion of the leg, means for securing the shin portion of the leg t-o said shaft for pivotal movement with respect to the thigh portion, an arm carried by said shaft in frictional engagement therewith and arranged to contact the thigh portion of the leg after the shin portion has llexed a determined amount whereby further flexion of the shin portion is yieldably retarded.

9. A knee mechanism according to claim 8 wherein said arm is arranged to interpose itself between the shin porti-on and the thigh portion of the leg upon predetermined extension of the former.

l0. A knee mechanism for an artificial leg having a shin portion and a thigh portion which mechanism comprises a shaft rotatably supported by the thigh portion of the leg, means for securing the shin portion of the leg to said shaft for pivotal movement with respect to the thigh portion, an arm carried by said shaft and arranged to contact the thigh portion upon predetermined flexion or extension of the shin portion of the leg whereby limits of flexion and extension are determined, first control means including a member in frictional engagement with said shaft to provide resistance to pivotal movement of the shin portion of the leg, and second control means including a member in frictional engagement with said shaft operative in response to predetermined pivotal movement of the shin portion to provide added resistance to further pivotal movement of the shin portion of the leg.

11. A knee mechanism for an artificial leg having a shin portion and a thigh portion, which mechanism com prises means pivotally mounting the shin portion on the thigh portion of the leg for movement between flexed and extended positions, and control means operative in response to predetermined movement of the shin portion from either of said positions toward the other to retard further pivotal movement.

12. A knee mechanism for an artificial ieg having a shin portion and a thigh portion comprising a shaft, rotatably supported by the thigh portion of the leg, means for securing the shin portion of the leg to said shaft for pivotal movement of said shin portion between flexed and extended positions, first control means operative in response to a predetermined flexing of said shin portion to retard further flexing thereof, and second control means carried by said shaft in frictional engagement-therewith Iand arranged to contact the thigh portion of the leg after the shin portion has flexed beyond said predetermined amount to further retard continued flexing of said shin.

References Cited in the file of this patent UNITED STATES PATENTS 2,327,042 Hinkle Aug. 17, 1943 2,424,078 Connor July l5, 1947 2,559,446 Lucas et al. July 3, 1951 2,645,779 Barghausen July 21, 1953 2,662,228 Bennington Dec. 15, 1953 2,698,947 Dumelin Jan. l1, 1955 .FOREIGN PATENTS 143,220 Australia Sept. 5, 1951 

